BIOLOGICAL DATA AND HABITAT REQUIREMENTS

WILDLIFE SPECIES: Drymarchon corais
TIMING OF MAJOR LIFE HISTORY EVENTS :
Indigo snakes can grow as long as 125 inches (262 cm). They mate from
November through March with a peak in mid-November through late
December. The age of sexual maturity is unknown [9]. An average of 3
to 10 eggs are laid in March through July; eggs hatch from May through
October [10]. The average life span of the indigo snake is 11 years,
although they can live as long as 21 years [11]. They do not hibernate
and remain somewhat active during winter, especially if temperatures are
higher than 50 degrees Fahrenheit (10 deg C) [9].
PREFERRED HABITAT :
Indigo snakes frequent flatwoods, hammocks, dry glades, stream bottoms,
cane fields, riparian thickets, and high ground with well-drained, sandy
soils [11]. In Georgia, snakes prefer excessively drained, deep sandy
soils along major streams, as well as xeric sandridge habitats [1].
Xeric slash pine plantations seem to be preferred over undisturbed
longleaf pine habitats [6]. Habitat selection varies seasonally. From
December to April indigo snakes prefer sandhill habitats; from May to
July snakes shift from winter dens to summer territories; from August
through November they are located more frequently in shady creek bottoms
than during other seasons [9].
COVER REQUIREMENTS :
Because the cover requirements of indigo snakes change seasonally,
maintaining corridors that link the different habitats used is
important. From the spring through fall snakes must be able to travel
from sandhill communities and upland pine-hardwood communities to creek
bottoms and agricultural fields [9]. In winter indigo snakes den in
gopher tortoise burrows, which are usually found in open pine forests
with dense herbaceous understories [6]. Burrows need to be in areas
where there is no flooding. Indigo snakes also heavily use debris piles
left from site-preparation operations on tree plantations [6]. These
piles are often destroyed for cosmetic reasons but should be left intact
because they provide important hiding cover for both the snake and its
prey. Summer home ranges for the indigo snake can be as large as 273
acres (229 ha) [9].
FOOD HABITS :
Indigo snakes eat other snakes, turtles, lizards, frogs, toads, a
variety of small birds and mammals, and eggs [6,11].
PREDATORS :
Humans represent the biggest threat to indigo snakes. Highway
fatalities, wanton killings, and overcollection for the pet trade
adversely affect indigo snake populations. Snakes are taken illegally
from the wild and sold as pets for as much as $250 each. Snakes are
also inadvertantly gassed in their burrows by rattlesnake hunters [1].
MANAGEMENT CONSIDERATIONS :
Indigo snakes are a commensal species associated with gopher tortoises.
Snakes use abandoned tortoise burrows heavily in the winter and spring
[1]. For this reason it is necessary to maintain healthy tortoise
populations, also a species in decline throughout its range. Because
slash piles are used by snakes for hiding and foraging, this debris
should be left intact on pine plantations [6]. Speake and others [9]
recommend protecting several thousand hectares of prime indigo snake
habitat to ensure the snakes' year-round needs are met. Some important
sandhill communities of Georgia and Florida are being replaced by slash
pine plantations, which can support a few snakes if burned and planted
with wide spacing to encourage gopher tortoise populations [6].
Recommendations for captive breeding of indigo snakes are as follows
[10]: Captive snakes should be released to the wild after 2 to 3 years,
and new snakes from the wild should be introduced to the captive
population, preferably every winter. This is important because wild
snakes seem to grow faster and produce more young than snakes held in
captivity. Because smaller snakes do not use tortoise burrows, they
should be released in wetland areas with plenty of herbaceous cover near
the water's edge. Hatchlings will den in areas with dense saw palmetto
(Serenoa repens) and should be released near these areas.

FIRE EFFECTS AND USE

WILDLIFE SPECIES: Drymarchon corais
DIRECT FIRE EFFECTS ON ANIMALS :
Because hatchlings do not use tortoise burrows they may be susceptible
to fire mortality. However, adult snakes may be able to escape fires
while in their burrows [10].
HABITAT RELATED FIRE EFFECTS :
Fire exclusion in southern pine-scrub oak habitats is a major cause of
habitat degredation for gopher tortoise and, therefore, indigo snakes
[6]. The absence of fire allows oaks to mature and leaf litter to
accumulate, making burrow digging difficult and herbaceous food scarce.
Studies of herpetofauna in Florida sandhill commmunities showed higher
species diversity in young sand pine (Pinus clausa)-scrub oak habitats,
which are maintained by frequent fire [7]. Experimental burns in these
communities showed snakes used plots burned at 2- and 7-year intervals
more than plots left unburned or burned yearly. The effects of
different season burns on gopher tortoises in Ocala National Forest,
Florida, showed more burrows in July-burned areas than in
February-burned areas at the first postfire year [8]. Preburn densities
of gopher tortoise were not determined.
FIRE USE :
Landers and Speake [6] recommend burning indigo snake habitats every 2
years to maintain a young, open overstory and an abundant herbaceous
understory. This will provide good gopher tortoise habitat, which in
turn will provide burrows for snakes. Burning sandhill communities
every 2 to 4 years will maintain open longleaf pine stands with
understories of wiregrass (Aristida stricta) and turkey oak [6].
Burning in late summer where young indigo snakes have been released from
captive breeding programs is not recommended because young snakes depend
on dense herbaceous vegetation for cover instead of burrows [10].